They say the position of leadership can cause one to grow faster. This happens because once we are given responsibilities, the mere struggle of trying to meet up to those responsibilities will eventually lead to growth. In the church system the congregation are mostly passive, they have almost no responsibility. All they have to do is make it to church, dance and sing when it's dancing and singing time, shout hallelujah when they are asked to shout hallelujah, sit when they are asked to sit, stand when they are asked to stand, basically they are just like dummies wanting for the people on the pulpit to tell them what to do.
When people are abandoned to such a state it becomes difficult for them to grow. But give them some responsibilities and just watch how fast they will grow. This is why there will be faster growth among Christians in ecclesia then in church. In the ecclesia, everyone has a responsibility to go draw from God and share with the group. The only reason pastors tend to be the most spiritually mature people in the church is because they are overlaid with the responsibility to have a sermon every Sunday and strengthen the rest of the church.
As such the pastors have to spend more time with the word, they have to study it harder, and they have to press hard on God to give them a word. But the other members of the church do not have such responsibility, so they don't care. I remember one time in school I was studying my Bible on my bed, and I hard four Bibles (different translations) spread out on that bed. I was seriously digging into the Scripture. My roommate saw me and was like, "Do you really need to kill yourself over it, you are not even the pastor, just read the one you can read and go your way".
This same roommate had read his bible that morning, but he did it religiously, "after all I am not the pastor", he must have thought to himself. In the church we've encouraged this mentality that since you are not the pastor then you don't need to know how to heal, perform miracle, preach the word, communicate with people on a spiritual level and draw them close to God, pray for people, encourage them, and inspire them. But if you are a pastor and you can't do these things, then you know you are going to lose your job or your members.
Pastors spend more time praying and fasting because they need to manifest power otherwise their reputation suffers. They need to know enough scripture, preach more eloquently, be more friendly and caring, and show concern for the people, drawing closer to them to know them and know the problems they are going through. If they don't do this their job will suffer, they might lose members and offering baskets will become empty, and they will have no food. They have a responsibility, and this responsibility have force them to grow in status.
Imagine all the members having this same responsibilities, but with different motivations (more godly motivations). They all have to study the bible otherwise the fellowship will be boring. Each member have to press hard to get a word from God for specific persons or for the general congregation. They must all draw each other close to know each other problems, for they are all responsible for each other. No member can keep to himself, he must open up, he must care for the other, show concern and get intimate with others.
If anyone is sick everybody is responsible for getting that person healed. If no one could do it then shame on the whole assembly. If something terrible should happen to any member, everybody is responsible, because they should have seen it before it happened, they should have been praying and interceding for one another until God show them what is coming and how to avert it. They are all responsible, and this responsibility will cause each one of them to grow.
As an ecclesia member you know that if you don't grow your beloved brethren with suffer, and because of your love for them you cannot remain immature. You want to help, you want to be a source of blessing to the assembly, and as you press like this you are growing faster than you would have imagined. That's the beauty of ecclesia.